Method of removing he at- sealed



Patented Apr. 7, 19 53 METHOD @lF REMOVING HEAT-SEALED ADHESIVE LABELS Arthur G. Quimby, Brookline, and Joseph A. Vencdam, East Boston, Mass., assignors to Doc & Ingalls, Ina, Everett, Mass, a corporation of Massachusetts No Drawing.

OFFICE Application November 14, 1950,

Serial No.-195,708

3 Claims. (Cl. 1 3j429) Our present invention is directed to a novel method of removing heat-sealed adhesive labels and is an improvement on the method set forth in our prior and copending application Ser. No. 91,236, filed May 3, 1949.

As explained in our said prior application, various methods have recently been developed for securely attaching labels or the like to such solid surfaces as glass, metal, synthetic plastic, or the like articles wherein the labels have been intimately bonded to the articles by resinous or other adhesives and secured by heat and pressure. This heat-sealing method is most desirable and also most important in the use of such trademark containers as beer bottles or the like, wherein the container was of sufiicient value or importance to be returned for re-use and refilling, and where it was equally important to have the label so securely attached as to prevent it being accidentally removed, marred, or injured thru ordinary handling, particularly Where sub- J'ected to the usual type of rough handling of heavy articles in transportation, delivery, storage, and the like.

While such heat-sealed attachment was thus highly desirable, it has heretofore been so difficult, expensive, and time-consuming to remove such heat-sealed labels as to largely limit and prevent the general use of these desirable heat-sealed, label-attaching methods, which old labels had to be removed for re-labeli'ng.

The ordinary bottle-cleaning, soaking, and label-removing processes did not act on a heatsealed label, nor would such ordinary soaking and cleaning processes remove the adhesive substance which had been thus intimately bonded on the surface of the container by the heat and pressure incident to the label-attaching operations.

In our development and experimentation of a composition of matter for the speedy de-labelizing of heat-sealed articles and the like, we find that We can advantageously employ a trisodium phosphate mixed with trisodium polyphosphate either with a suitable wetting agent or without.

We have designated our new compound as Elo No. 10, and the same comprises an admixture of substantially fifty per cent of trisodium phosphate and fifty per cent of trisodium polyphosphate mixed together as a dry powder. In case a wetting agentis added, the proportions would be approximately 49 of trisodium phosphate and 49 of trisodium polyphosphate, and 1% of a suitable wettingagent, thus producing 100% of the compound which is mixed, in either formula, in a proportion of four to eight ounces of the composition of matter to a gallon of water and operatively employed at a temperature range of to F.

When a wetting agent is employed, we prefer to utilize sodium laurel sulphate, 1% of the same being found usually sufficient as above set forth in the proportions indicated.

Our compound as above set forth, including the wetting agent, is applied to one or more of the soaking tanks in the usual type of bottle-cleaning apparatus, either with or without bafiies. Also we can apply the composition of matter in the first soaking tank and,'thereafter, apply a spray of the composition of matter, without the wetting agent, under thirty to fifty pounds pressure and at slightly increased temperatures, thereby speedily and effectually removing all traces of the bonding element.

We find that it is also possible to rely entirely upon the spraying operation to effectually and thoroughly de-labelize heat-sealed labels or the like on any such solid container as above defined. Either soaking alone, spraying alone, or a combined soaking and spraying is completely effective in a relatively few minutes, one to five minutes, for the entire series of operations being ordinarily sufficient to de-labelize and remove the bonding residue.

The composition of matter and proportions as above set forth are those which we consider at present as preferable, but it will be appreciated that equivalents and slight changes in the proportions named may be employed with satisfactory results, such variations being often desirable for use on different types of adhesives employed.

We believe that our discovery of the employment of the type of phosphates above listed, either with a wetting agent, or without, for the purpose herein explained is distinctly new in this art in connection with the process of the heated soaking and spraying under substantially the pressures and temperatures as set forth and we are entitled to claim the same herein broadly.

Also, while we have set forth our invention as primarily directed to de-labelizing processes, our invention can be employed efficiently for efiectually cleaning and sterilizing containers or other articles of metal, glass, synthetic plastic, or the like solid substances, and is also efiicient in the prevention, removal, or control of scale formed in tanks.

We claim:

1. That improvement in the art of removing heat-sealed substances from the surface of an article which consists in supplying a solution containing a composition of matter of substantially fifty per cent of trisodium phosphate, and fifty per cent of trisodium polyphosphate, mixed in the proportions of from four to eight ounces to a gallon of water, heating and applying the same to the surface of such article at a temperature range of from 105 to 185 F.

2. The process as set forth in claim 1, whereina duplicate composition of matter under thirty to fifty pounds pressure and at a temperature of from 105 to 185 F. is subsequently applied to such surface as a spray.

3. That improvement in the art of de-l'abelizing labels or the like which have been adhesively attached to the exterior of metal, glass, or synthetic plastic containers by heat. and pressure, which consists in soaking the same in a composition of matter of substantially fifty per cent. of trisodium phosphate, and fifty per cent of trisodium polyphosphate in a dry state, mixed in the proportions of from four to eight ounces to a gallon of watenand heated to a temperature range of from 105 to 185 F., and subsequently applying as a spray a duplicate composition of matter under thirty to fifty pounds pressure and at a higher temperature to the containers.

ARTHUR G. QUIMBY. JOSEPH A. VENEDAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,383,470 Morgan Aug. 28, 1945 2,549,805 Grenstad Apr. 24, 1951 

1. THAT IMPROVEMENT IN THE ART OF REMOVING HEAT-SEALED SUBSTANCES FROM THE SURFACE OF AN ARTICLE WHICH CONSISTS IN SUPPLYING A SOLUTION CONTAINING A COMPOSITION OF MATTER OF SUBSTANTIALLY FIFTY PER CENT OF TRISODIUM PHOSPHATE, AND FIFTY PER CENT OF TRISODIUM POLYPHOSPHATE, MIXED IN THE PROPORTIONS OF FROM FOUR TO EIGHT OUNCES TO A GALLON OF WATER, HEATING AND APPLYING THE SAME TO THE SURFACE OF SUCH ARTICLE AT A TEMPERATURE RANGE OF FROM 105* TO 185* F. 